Pulp drainer



Sept. 27, 194-9. A. J. HAUG ,2 0

PULP DRAINER Filed March 24, 1945 5 Sheets-Sheet l ("a I I A- I I I ll lI I I I I I q g l O I L i I 5 1 I l 6 I m I o f) I 1" I I h n l o g I II I l I I 0) Q?- l I I o I l l X a I I I I L.:.: i v

m I i Sept. 27,1949. A. J. HAUG 2,433,200

PULP DRAINER Filed March 24, 1945 5 Sheet-Sheet 2 \9 g M 13 a Q m I A A0 Q Q Q o o Sept. 27, 1949. A. J. HAUG 2,483,200

PULP DRAINER Filed March 24, 1945 5 Sheets-Sheet 5 Sept. 27, 1949. A. J.HAUG' 2,483,200

\ PULP DRAINER Filed March 24.31945 5 Sheets-Sheet 4 p 7; 1949. A. J.I-I-IAUG 2,483,200

PULP DRAINER Filed March 24, 1945 5 Sheets-Sheet 5 Patented Sept. 27,1949 UNITED STATES PATENT OFFICE PULP DRAINER Anton J. Haug, Nashua, N.H.

Application March 24, 1945, Serial No. 584,619

This invention relates to that class of machines known as drainers. Theyare used, for example, in the paper-making process preceding the refinerto remove excess water from the stock to be refined, and thus to placethis stock in better condition for the refining operation.

The present invention aims to improve machines of this type with a viewparticularly to increasing their efliciency, reducing the cost ofmanufacture of them, and facilitating the servicing operations on them.The manner in which it is proposed to accomplish these objects will bereadily understood from the following description when read inconnection with the accompanying drawings, and the novel features willbe particularly pointed out in the appended claims.

In the drawings,

Fig. 1 is a vertical, longitudinal, sectional view through one endportion of a drainer constructed in accordance with this invention;

Fig. 2 is a similar view through the opposite end portion of themachine;

Fig. 3 is an end elevation of the part of the machine shown in Fig. 2;

Fig. 4 is a sectional view taken approximately on the line 4, Fig. 1;

Fig. 5 is a similar view on substantially the line 5--5 of Fig. 2; and vFig. 6 is a perspective view of the arm which supports the press roll.

Referring first to Figs. 1 and 2, the construction there shown comprisesa casing, indicated in general at 2, and including an end casting 3provided with an intake chute l and also with another end casting 5having an outlet or discharge passage 6 for the solid constituents ofthe papermaking stock. Mounted in this casing is a revolving screen drum1 and inside the drum is a screw conveyor 8 which feeds the stockdelivered into the screen lengthwise thereof toward the outlet 8.

Drainers organized in this general manner hav been used heretofore, andone of the objectionsto them has been the fact that the manufacture ofthe screw conveyor and of the screw and screen assembly is a veryexpensive matter. Important objects of this invention, therefore, are toovercome this difiiculty, to devise a better fprm of screw conveyor, andto improve the screen and screw combination so that both can. bemanufactured, assembled and repaired 'more easily-and 13 Claims. (Cl.92--35) part 9 and cooperating with it to form a chamber in-the screendrum into which the stock is initially delivered by the intake chute 4.These two castings 9 and 9' are bolted together so that, in effect, theyform a single integral structure, but they are divided on a diametralplane for convenience of manufacture and assembly.

Secured at points spaced equally around the circumference of the twoheads 9 and ID are four bars l3, as best shown in Fig. 4, the ends ofthese bars being bolted or riveted to ears I4 and it: which are boltedto the flanges of the heads 9 and I0, respectively. The screenpreferably consists of four curved perforated plates, each of the entirelength of the main screen section and each having a circumferentialextent of approximately The longitudinal edges of each screen sectionabut against two of the bars l3 and are secured to them by angle barsl6, two of which are bolted or riveted to opposite sides of each bar l3.

Opposite ends of each screen plate overlie the inner reduced marginalperipheral portions of the heads 9 and I0. Thus the installation,removal, or replacement of any screen plate can be readily accomplished.

The screw itself also .is of novel form and is made up of severalsections of sheet metal, initially pressed to the desired shape, andthen buttwelded together, edge to edge. The two ends of this screw aresecured, respectively, to the heads 5. and i0 and both of these headspreferably are provided with surfaces which have the same screwformation, contour and pitch as the screw itself, so that the screwassembly includes all three of these elements and all of them contributeto the function of feeding the stock from the inlet to the outlet of themachine.

Circumferential support for the screw is provided by fashioning smallbosses at on the inner edges of the bars l3 and slotting these bosses atthe right angle and at proper distances apart to receive and support theouter edges of the convolutions of the screw. This makes a very sturdyeconomically than has been possible in prior art constructions.

In the construction shown in Figs. 1 and 2, the

screen assembly comprises two heads or end castings 9 and i0,respectively, both mounted on a shaft l2 which is supported in bearingsin the two end frame castings 3 and 5 above referred to. Cooperatingwith the casting 9 at the intake end of the machine is another casting9' bolted to the and substantial construction. with a smooth screensurface inside, particularly if care is taken to make the edges of 'thescreen plates substantially flush with the inner edges of the'bars' l3where they abut against the latter.

Assembly of this screw and screen unit may be conveniently performed bypressing the heads 9 and ID on the shaft I2 in their final positions,and threading the screw 8 on to the shaft, starting at one end andrevolving it while at the same time twisting it as may be necessary tothread it on to the section of the shaft between the heads. Initiallythe screw is disposed at about right angles to the shaft, but as theinstalling operation proceeds, it is twisted so as to maintain the shaftin the hole in successive turns of the screw while this installingoperation is completed. There 3 after the ends are fastened to the twoheads 8 and I by a few rivets. Later the bars I3 are secured to theheads, the edges of the screw are fitted into the slots provided in thelugs a to receive and support them, and the screen sections I aresecured to the bars as above described.

In this connection it should be noted that the internal diameter of thescrew is considerably larger than that of the shaft, and that factfacilitates the assembling operation just described. When this operationhas been completed, the inner edges of the convolutions of the screw arespaced by a considerable radial distance from the shaft I2.

At the end of the main screen section I a second screen section I isprovided which tapers, or is frusto-conical in form, its smaller endbeing Joined to the end casting I0. As shown, the frame for this secondsection comprises a ring N, Fig. 2, of channel section, and a bodyportion I8, made in four 90 sections, which are bolted together and alsoare bolted to the ring II and the end flange of the head Ill. Thesesections of the body portion l8 are flanged or ribbed deeply, bothcircumferentially and longitudinally, so that, when secured together,they form a very strong, rigid structure. Screen plate sections, similarto those of which the screen I is composed, are secured to the innersurfaces of the body portion I8. This section forms the delivery end ofthe screen drum, and it opens directly into the discharge passage 6above referred to. Operating in the conical section I of the screen is apress roll which revolves freely on a shaft 2I supported by an arm 22,Fig. 2, 3 and 6. The upper end of this arm is bolted to a bracket 23,and the latter carries a shaft 24, Fig. 3, extending parallel to theshaft I2 and mounted to rock freely in the stationary bracket ortrunnion which is bolted on a shelf portion of the end frame casting 5Secured to the bracket 23 is an elongated arm 26, Fig. 3, on which isslidably mounted a weight 2'! adapted to be locked in any position ofadjustment by a wing nut 28. As will be readily observed from aninspection of Fig. 3, the weight tends to hold the roll 20 constantlypressed against the inner surface of the conical screen I. Usually thisroll is provided with a rubber or equivalent surface, and it often isgrooved to reduce slip.

In the operation of this drainer, stock derived from several sourcessuch, for example, as the material rejected by the pulp screens, is fedinto the intake chute 4, the materialat this time usually containing ahigh percentage of water. That is, the solid constituent, in a typicalcase, is from. about one-third of one percent. to two percent. of theentire weight of the material. It can therefore be flowed through theinlet freely and promptly comes into contact with the inner surface ofthe screen I. As the feeding operation continues and the screenrevolves, the stock is advanced lengthwise of the screen toward thedischarge outlet, and it loses water by gravity during its entiretravel. It is finally forced by the screw into the conical section Iwhere it issubjected to the action of the press roll 20 which squeezesadditional water out of the stock.

At this time the water content may be reduced to in the neighborhood of,say, 80% of the total weight of the material. The latter is fairly solidand very crumbly so that it rattles freely through the discharge outlet6 into the refiner or any other desired apparatus or receptacle.

It is important to the satisfactory operation of the press roll that itbe set so as to bear evenly against the inner surface of the conicalscreen section 'I when no stock is interposed between the roll and thescreen. This has been difli- 5 cult to accomplish in priorconstructions, and for this reason the construction above described hasbeen provided. In it the meeting faces of the arm 22 and bracket 23 arelocated at such an angle that the arm may be moved about an axisperpendicular to said faces, so as to adjust the axis of the press roll20 angularly in a radial plane passing substantially through the axis ofthe shaft i2 and then locked in its adjusted position. The latter axisis also the axis of the conical screen section. Consequently, with thisadjustment the pressure with which successive longitudinal portions ofthe press roll bear against the screen can be varied, as desired, tomake the roll bear evenly for its entire length on the screen- As shownin Fig. 6, the holes in the upper flanged end of the arm 22, throughwhich the bolts 22 pass, are slotted on a circumference concentric withthe axis of the arm to permit this adjustment.

A particularhr troublesome problem in the operation of a drainer of thistype is the fact that the stock fed into it contains a high proportionof slivers. They find their way into the holes of the screen and getstuck there. As this action continues the efliciency of the screenbecomes materially reduced. The usual scraper constructions arethoroughly unsatisfactory in dealing with this condition. I have found,however, that by using a yieldingly surfaced scraper which bends overalong the inner circumference of the screen due to the drag of thelatter, the slivers will be pulled out by it. Such a construction isshown in Figs. 2 and 5 in which the scraper 28 consists of a strip ofthick canvas belting, or the like, secured to the bar 30, this bar beingbolted to a bracket 3|, Fig. 3. It is made long enough to provide aconsiderable length which is bent over by its contact with the screenwhere it exerts a strong dragging action on the slivers serving to pullthem backwardly out of the holes in the screen in which they are lodged.

The machine may conveniently be supported on channel bars 3232, set upedgewise, the end castings 3 and 5 being shaped to set on them andhaving flange or web sections which span the distance between the bars32-32. Portions of the end castings 3 and '5 determine the shape of thecasing 2, and the latter is preferably made up of three sectionsa bottomsection 20., Fig. 4, and top sections 2b and 2c. The two latter sectionsare each of 90 in angular extent and the bottom section is 180. Thewater extracted from the stock collects on the upper surface of thebottom section 2a, as will be seen from an inspection of Figs. 1 and 2,and it runs by gravity toward the intake end of the machine where it isled off by pipe connections bolted to the flanged ends dd, Fig. 1, ofthe end casting 3.

Shower pipes 33-33 are so positioned and arranged as to direct sprays ofwater more or less tangentially against the on-coming surface of thescreen to clean it.

Throughout the body of the screen, if perforated metal plates are used,I prefer. for ordinary pulp, to make the perforations about an eighth ofan inch in diameter and to use approximately thirty-two holes per squarefoot. In the'conical section, however, it is sufllcient to use aconsiderably smaller number say, for exam- 7 pie, eighteen holes persquare foot. The size and type of perforations necessarily will vary inaccordance with the material being handled. In draining some kinds ofstock, a wire mesh is entirely suitable. For the screw 8 I have obtainedgood results by making it of fairly thin stock, say one-eighth orthree-sixteenths of an inch in ,thickness, preferably, but notnecessarily, of bronze. It is stiff enough so that no fastenings, otherthan those necessary to secure it to the heads, are required. It mayconveniently be removed for renewal by cutting or drilling out therivets which secure it to the heads; taking off the bars l3; andreversing the installing operations above described.

It will be evident from the foregoing that this invention provides adrainer of such a construction that the cost of manufacture of it isvery materially reduced, other factors being equal, as compared with theprior art constructions. Also, that the servicing or repairingoperations which may later become necessary may be performed more easilyand economically. In addition, the efiiciency of the machine has beenincreased, more particularly because there is less opportunity forplugging the screen, and for the accumulation of stock in it at pointswhere the draining action would be impeded.

While I have herein shown and described a preferred embodiment of myinvention, it will be evident that the invention is susceptible of embodiment in other forms without departing from the spirit or scopethereof.

Having thus described my invention, what I desire to claim as new is:

1. A pulp drainer comprising the combination of an elongated casingprovided with a stock inlet at one end and a stock outlet at the otherend, a screw for feeding the stock lengthwise of the casing toward saidoutlet, a screen drum encircling said screw, said screw comprising ametal strip coiled edgewise around its axis of rotation, and a supportfor said screw comprising a plurality of bars extending lengthwise ofand spaced circumferentially around said screw, means for supportingsaid screen drum on said bars, guide means on the bars adjacent theinner edges thereof for guiding the edges of said screw on said bars butbeing free from rigid attachment to the bars, whereby the screw can beremoved while some of said bars remain in place.

2. A pulp drainer comprising the combination of an elongated casingprovided with a stock inlet at one end and a stock outlet at the otherend, a screw for feeding the stock lengthwise of the casing toward saidoutlet, a rotary screen drum encircling said screw, means for supportingsaid drum for rotary movement, said screw comprising a metal stripcoiled edgewise around its axis of rotation, rigid heads at oppositeends of said screw, and a series of bars mounted at their ends on saidheads, means for supporting said screen drum on said bars, said barshaving transverse slots in which the outer edge portions of said screware supported but being free from rigid attachment to said bars, wherebythe screw can be removed or replaced while some of the bars remain intheir normal positions.

3. A pulp drainer comprising the combination of an elongated casingprovided with a stock inlet at one end and a stock outlet at the otherend, a screw for feeding the stock lengthwise of the casing toward saidoutlet, a rotary screen drum encircling said screw, means for supportingsaid drum for rotary movement, said screw comprising a metal stripcoiled edgewise around its axis of rotation, a supporting shaftextending through said screw coaxially therewith, two rigid headsmounted on said shaft, a series of bars extending parallel to said shaftand secured to said heads, said bars being spaced circumferentiallyaround said screw, the inner edges of said bars being slotted to receiveand support the outer edges of the convolutions of said screw withoutbeing fastened rigidly to the screw, said drum also being supported onsaid bars at the inner edges thereof and having a substantially smoothinner surface.

4. A pulp drainer comprising the combination of an elongated casingprovided with a stock inlet at one end and a stock outlet at the otherend, a screw for feeding the stock lengthwise of the casing toward saidoutlet, a screen drum encircling said screw, said screw comprising ametal strip coiled edge'vise around its axis of rotation, a supportingshaft extending through said screw coaxially therewith, bearingssupporting said shaft, two rigid heads mounted on said shaft, said headsbeing provided with surfaces which form continuations of uninterruptedscrew shape of the stock-propelling surfaces of the screw and whichcooperate with the screw to feed the stock lengthwise through the drum,the two heads forming supports for the screen drum and the screw.

5. A pulp drainer comprising the combination of an elongated casingprovided with a stock inlet at one endand a stock outlet at the otherend, a screw for feeding the stock lengthwise of the .casing toward saidoutlet, a screen drum encircling said screw, said screw comprising ametal strip coiled edgewise around its axis of rotation, a supportingshaft extending through said screw coaxially therewith, 'two rigid headsmounted on said shaft and supporting the opposite ends of said drum, aplurality of bars supported on said heads and extending parallel to theaxis of said drum, means on the bars adjacent the inner edges thereoffor guiding the screw on said bars and to support the portion of saiddrum between said heads on said bars at the inner edges there of, theentire supporting means for that portion of the drum between said headsbeing located externally of the drum and the inner surface of said drumbetween said heads being substantially smooth and unobstructed by theparts which support it.

6. A pulp drainer comprising the combination of an elongated casingprovided with a stock inlet at one end and a stock outlet at the otherend, a screw for feeding the stock lengthwise of the casing toward saidoutlet, a screen drum encircling said screw, said screw comprising ametal strip coiled edgewise around its axis of ro tation, a supportingshaft extending through said screw coaxially therewith, two rigid headsmounted on said shaft and supporting both the opposite ends of said drumand also the opposite ends of said screw, a plurality of bars supportedon said heads and extending longitudinally of said drum, said bars beingspaced circumferentially around the drum, means on the bars adjacent theinner edges thereof for guiding the screw on said bars to support theportions of said drum between said heads on the inner edges of saidbars, the outer edge portions of said screw between said heads alsobeing supported on the inner edges of said bars but free from attachmentto said drum, the inner surface of said drum between said heads beingsmooth and unobstructed by the parts that support it.

"I. A pulp drainer comprising the combination of an elongated casingprovided with a stock inlet at one end and a stock outlet at the otherend, a screw for feeding the stock lengthwise of the casing toward saidoutlet, a screen drum encircling said screw, said screw comprising ametal strip coiled edgewise around its axis of rotation, a supportingshaft extending through said screw coaxially therewith, bearingssupporting said shaft, two rigid heads mounted on said shaft andpositioned at opposite ends of said drum, a series of bars extendingparallel to said shaft and secured to said heads, said bars being spacedcircumferentially around said screw, the ends of said screw beingsupporting on said heads and the heads being provided with surfaceswhich form continuations of the stock-propelling surfaces of the screwand which cooperate with the screw to feed the stock lengthwise throughthe drum, both said drum and said screw being supported by said bars atthe inner edges of the bars.

8. A pulp drainer according to preceding claim 6, in which said drum iscomposed of pre-shaped partial circumferential sections and said meansfor supporting said drum includes parts releasably secured to said barsand said heads for holding said sections normally but releasably intheir operative positions so that any section can be removed andreplaced independently of an adjacent section, the entire supportingmeans for said drum between said heads being external to the drum.

9. A pulp drainer comprising the combination of an elongated casingprovided with a stock inlet at one end and with a stock outlet at theend,-

a rotary screen extending lengthwise of said casing, said screen havinga smooth substantially uninterrupted inner surface, means for feedingthe stock longitudinally through said screen toward said outlet wherebysurplus water drains outwardly, and a scraper blade, means forsupporting said scraper in a substantially stationary position in firmbut yielding contact against the smooth interior surface of a portion ofthe screen so that said scraper blade is bent over by its contact withthe screen, thereby providing a dragging surface cooperating with themotion of the screen to drag the slivers stuck in the holes in thescreen inwardly out of it.

10. A pulp drainer comprising the combination of an elongated casingprovided with a stock inlet at one end and with a, stock outlet at theother end, a rotary screen drum extendingjlengthwise of said casing,means for feeding the stock longitudinally through said drum toward saidoutlet, an additional screen section of frusto-conical form coaxial withsaid drum and positioned at the delivery end thereof into which thepartially drained stock is delivered by the drum, said additional screensection having a substantially smooth interior surface, a press rollmounted in said conical section for swinging movement in to and out ofcontact with thestock on the screen surface of the latter section,whereby said roll is operable to press the stock against the conicalscreen section to force additional water out of it, a yieldinglysurfaced scraper mounted within the additional screen section, and meanssupporting it in a substantially fixed position with its yieldingsurface bearing against the inner surface of the latter screen section,said scraper comprising a blade having a surface shaped to drag theslivers stuck in the screen inwardly out of it.

11. A pulp drainer comprising the combination of an elongated casingprovided with a stock inlet at one end and'with a, stock outlet at theother end, a rotary screen extending lengthwise of said casing, saidscreen including a portion having a smooth, substantially uninterruptedinner surface, means for feeding the stock longitudinally through saidscreen toward said outlet whereby surplus water drains outwardly, ascraper, means for supporting said scraper in a substantially stationaryposition in firm but yielding contact against the smooth interiorsurface of a portion of the screen, said scraper being bent over by itscontact with the screen and thereby providing a. dragging surfacecooperating with the motion of the screen to drag the slivers stuck inthe holes in the screen inwardly out of it, said rotary screen having asection of substantially frusto-conical form and having a screensurface, means supporting a press rolLso that said roll is positionedwithin said conical section for swinging movement toward and from thescreen surface of the frusto-conical section, whereby said roll isoperable to press the stock against the latter screen surface to forceadditional water out of it, and means supporting said press roll'forangular adjustment relative to said screen surface to vary the degree ofpressure with which 'diiferent portions of the roll bear against saidsmooth interior surface.

12. A pulp drainer according to preceding claim 11, in which thesupporting means for said press roll comprises a stationary bracket, anarm supporting said roll, and a swinging bracket mounted on saidstationary bracket for pivotal movement about an axis parallel with theaxis of said screen, said arm being supported on said pivoted bracketfor angular adjustment in a plane substantially 'intersectin the axes ofboth said frusto-conical screen and said press roll.

13. A pulp drainer according to preceding claim 11, in which thesupporting means for said press roll comprises a stationary bracket, anarm supporting said roll, a swinging bracket mounted on said stationarybracket for pivotal movement about an axis parallel with the axis ofsaid screen, means acting on said swinging bracket in a directiontending to force said press roll into contact with said inner peripheralsurface of said frusto-conical screen section, said arm being mounted onsaid swinging bracket for adjustment to vary the degree with whichsuccessive longitudinal portions of said press roll bear against saidfrusto-conical screen surface.

- ANTON J. HAUG.

REFERENCES CITED I The following references. are of record in the fileof this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,483,200September 27, 1949 ANTON J. HAUG It is hereby certified that errorappears in the printed specification of the above numbered patentrequiring correction as follows:

Column 7, line 36, before the word end, second occurrence, insert other;

and that the said Letters Patent should be read with this correctiontherein that the same may conform to the record of the case in thePatent Ofiice. Signed and sealed this 31st day of January, A. D. 1950.

THOMAS F. MURPHY,

Assistant Commissioner of Patentl.

